Improvement in belt-shifters



WILLIAM H. H. SISUM. Improvement in Belt-Shifters, 127 109 Patented May 21-; 18-72;

AM. PHOI'U-LITHUGHAFHI CQMY. (OSBGRNE S PROCESS) UNITED STATES PATENT QFFIcE.

. WILLIAMLH. n. sIsUM, or NEWARK, NEW JERSEY.

- H TIMI5ROVEMEVNT IN BELT-SHIFTERS.

Specification forming part of Letters Patent No. 97,109, dated May 21, 1872; antcdatcd May 20, 1872.

Specification describing certain Improvements in BeltShifters, invented by WILLIAM H. H. SISUM, of Newark, New Jersey.

' The invention is designed for shifting a single belt from a fast to a loose pulley, and the reverse. The shifting may be done by hand, and the shifter may be left entirely free after the belt has been thrown to either extremity of its traverse, and it will lock itself or hold itself by the powerful friction induced by its peculiar construction. Any tendency of the belt to run inone direction or the other induces a pull on the belt-shifter, which tends to disturb its position; but the constructioncauses any strain received in that manner to induce aforcible binding of the parts. I have designated this as a locking, though the term may be objected to, as it is a fastening depending solely on friction but the friction is sufiiciently strong to resist the yielding to a force derived through such source. But when the hand is applied, or any automatic action of the machine at the proper time to induce a movement of the beltshifter, it is applied at another point, and induces the motion with comparative ease. The force thus legitimately applied does notlock the parts, and, even in case a tendency of the belt to resist the motion might cause a slight lockin g force, the proper moving force applied with vigor can always move it. p

The following is a description of what I consider the best means of carrying out the invention.

The accompanying drawing forms a part of this specification. V

Figure 1 is a plan view. Fig. 2 is a vertical section on the line S S; and Fig. 3 is a vertical section on the line T T. These figures are all on the same scale, and represent the shifter as adapted to be operated by a cord. Fig. 4 represents, on a smaller scale, a modified form of the apparatus, in which the lever is provided with long arms, by which the lever is forcibly held in an easy position when the belt is being shifted by the force properly applied.

Similar letters of reference indicate corresponding parts in all the figures.

A is a slotted casting, adapted to be secured upon a post or other fixed object,and to allow the lever B to slide forward and backward thereon to a sufiicient extent. The lever B has a loop, B which receives the belt, and is capable of turning, to a' slight extent, on a center, 12, which is supported in a block, 0, which is guided on the rigid arm or frame A by means of lips 0 G which traverse on the upper and lower surfaces, as shown. The block O can not turn, but simply slides smoothly to one side and the other on the frameA'. The lever Bis bell-cranked or turned at right angles, the short arm carrying a pin, B which stands in the slot a in the frame A. v This pin may, for durability, be incased in a block, D, which. presents a wide bearing-surface in the slot.

N ow, it will be seen that any force applied by the edge of the belt, tending to run in either direction in the loop B at the long' arm of the lever, tends to induce a greatly-increased upward and downward pressure on the pin B and, consequently, to induce friction, either by the direct pressure of the pin B or, if a block, D, is employed, by the pressure of the block D upon the upper or lower side of the slot a. The friction thus induced is sufficient to resist the tendency to motion due to the action of the belt; but when the force of the hand is applied through any suitable rod or cord it is applied directly to the block (J, and preferably applied at its center, as represented by the cord m in the figure. The force thus applied induces no such friction, but applies directly to move the entire assemblage ofmovableparts from one end to the other of the slot a. 1t follows that the device may be operated easily by hand, and will hold itself firmly in position at either end of its traverse. It would hold itself in any intermediate position also, if desired in any case.

The proportions of the two arms of the bellcrank lever B B may be varied within wide limits without sacrificing all the advantages of my invention; but if the arm B be too greatly extended the frictional holding'force becomes so reduced that, in case the surfaces are very smooth and are oiled by accident or design, the device is liable to shift of itself. If, on the other hand, the arm B betoo much shortened, so that the crank-pin B is almost in line with the central turniu g pivot b, being only slightly eccentric thereto, it is liable not only to allow a disagreeable'shackling motion or looseness to the other arm, (the long arm carrying the loop B but it is also liable to produce a too great binding force. There is no particular evil resulting from a severe bind- .ing force while the device remains fixed at either end of its motion; but when the force of the hand is applied to the cord m or its equivalent to move the device a strong resistance, exerted at the moment by the belt on the loop B is liable to lock or jam the device so that the hand cannot move it. I believe that a proportion 'of four to one is the best for general purposes-that is to say, the loop 13, which receives and guides the belt is four times as far from the turning center I) as the pin 13", which stands in the slot a and induces the friction. I

I propose, in some instances, to apply an additional device, in connection with the cord m or other means through which the force of the hand or machine is transmitted to induce the legitimate shifting, which additional device shall have the effect of holding the parts in the unlocked condition whenever the shifter is to be operated or moved from one end of the slot a to the other. This may be done in various ways. One would be to have long arms extending from the turning part B B in the path of the cord m, as indicated in Fig. 4. -When the cord is slack these arms are of no efiect and the device serves as before; but when the cord is tightened, the force, being transmitted through the arm B or 13", tends to pull the turning part into the proper position to allow it to move readily. I believe, however, that such additions are unnecessary in ordinary practice.

I claim as my invention- In combination with the guiding and supporting'frame A a, or its equivalent, the unequal lever B B turning on a center, b, near which the force is applied to induce a shifting of the device, so arranged that a force received from the belt will induce a self-lockingor jamming, while a force applied through the proper means m may easily shift it, all substantially as and for the purposes herein set forth;

In testimony whereof I have hereunto set my name in presence of two subscribing wit;

nesses.

WM. H. H. SISUM. I

Witnesses:

O. 0. LIVINGS, ARNOLD HOERMANN. 

